For some time now there has been a working hypothesis that proposes an error in the metabolism of the indolealkylamines in human brain which may be related to the etiology of schizophrenia. This idea has been given new importance with the identification of certain transmethylating enzymes in brain tissue. In the light of these considerations we have developed a technique utilizing gas liquid chromatography which allows the identification of known psychotomimetic agents, derived from the tryptamine nucleus, at the picogram level in the cerebrospinal fluid (CSF) of psychotic patients. Briefly, the methodology used consists of extracting deproteinized human CSF with ultrapure methylene chloride at pH 12, evaporating the solvent, and derivatization of the residue with hepatafluorobutyryl imidazole. Excess reagent is destroyed by the addition of water and the acylated derivatives are taken up in ultrapure toluene and separated by gas-liquid chromatography on a 6 or 12 foot, 3 percent OV-17 column; the chromatograph was equipped with a Ni electron capture detector. A pure heptafluorobutyryl derivative was prepared and analyzed for each of the suspected tryptamine derivatives. The following compounds were identified in CSF: tryptamine, dimethyltryptamine, O-methylbufotenin, and 5-methoxytryptamine. The presence of each of these compounds was verified by spiking with the pure derivatives. At this point there appears to be a wide variability in the relative amounts of these agents in both patient populations. However, we have some 60-70 spinal fluids yet to analyze. Speculation at this point would indicate that dimethyltryptamine is the psychotogen responsible for the bizarre symptomology.